In order to study the fatigue failure mode and fatigue life laws of basalt-aramid and basalt-carbon hybrid fiber reinforced polymer （ FRP ） sheets, fatigue experiments are carried out, considering two hybrid ratios ...In order to study the fatigue failure mode and fatigue life laws of basalt-aramid and basalt-carbon hybrid fiber reinforced polymer （ FRP ） sheets, fatigue experiments are carried out, considering two hybrid ratios of 1 ： 1 and 2：1 under different stress levels from 0.6 to 0.95. The results show that fractures occur first in carbon fibers or aramid fibers for the specimens with hybrid ratio of 1： 1, namely B1A1 and B1C1, while a fracture occurs first in basalt fibers for the specimens with a hybrid ratio of 2： 1, namely B2A1 and B2C1. The fatigue lives of the hybrid FRP sheets increase with the improvement of the content of carbon fibers or aramid fibers, and the influence of the carbon fibers content improvement to fatigue life is more significant. The fatigue performance of B2A1 is relatively worse, while the fatigue performance of B1C1 and B2C1 is relatively better. Finally, a new fatigue stiffness degradation model with dual variables and double inflection points is presented, which is applicable to both hybrid and normal FRP sheets.展开更多
The high-strength Basalt Carbon Fiber Reinforced Polymer(BCFRP)composites had been manufactured by guiding Imitating Tree-root Micro/Nano Aramid Short Fiber(ITMNASF)into the interlayer of Basalt Fiber(BF)and Carbon Fi...The high-strength Basalt Carbon Fiber Reinforced Polymer(BCFRP)composites had been manufactured by guiding Imitating Tree-root Micro/Nano Aramid Short Fiber(ITMNASF)into the interlayer of Basalt Fiber(BF)and Carbon Fiber(CF)plies to form thin interleaving,and various mass proportions of IT-MNASF were designed to discuss the reinforcing effect on the BCFRP heterogeneous composites.The results of three points bending tests showed that flexural strength and energy absorption of 4wt%IT-MNASF reinforced BCFRP heterogeneous composites had been improved by 32.4%and 134.4%respectively compared with that of unreinforced specimens.The 4wt%IT-MNASF reinforced BCFRP specimens showed both a greater strength and a lower cost(reduced by 31%around)than that of plain CFRP composites.X-ray micro-computed tomography scanning results exhibited that the delamination-dominated failure of plain BCFRP composites was changed into multi-layer BF and CF fabrics damage.The reinforcing mechanism revealed that the introduced IT-MNASF could construct quasi-vertical fiber bridging,and it was used as"mechanical claws"to grasp adjacent fiber layers for creating a stronger mechanical interlocking,and this effectively improved resin-rich region and interfacial transition region at the interlayers.The simple and effective IT-MNASF interleaving technique was very successful in low-cost and high-strength development of BCFRP heterogeneous composites.展开更多
Compressive strengths and elastic moduli of Carbon Fiber Reinforced Polymer(CFRP)composites can be noticeably improved by multiple ultra-thin interlays with non-woven Aramid Pulp(AP)micro/nano-fibers.10-ply CFRP speci...Compressive strengths and elastic moduli of Carbon Fiber Reinforced Polymer(CFRP)composites can be noticeably improved by multiple ultra-thin interlays with non-woven Aramid Pulp(AP)micro/nano-fibers.10-ply CFRP specimens with 0,2,4,6,8 g/m^(2)AP were tested under uniaxial compression.Those flexible AP fibers,filling the resin-rich regions and further constructing the fiber bridging at the ply interfaces,can effectively suppress delamination growth and lead to very good improvements both in the compressive strength and the elastic modulus.The CFRP specimen with an optimum interlay thickness has a distinct shear failure mode instead of the typical delamination cracking along the direction of continuous carbon fibers.Compressive Strengths After Impacts(CAI)of 12.35 J were also measured,up to 90%improvement in CAI has been observed.It is concluded those ultra-thin interlays of non-woven AP micro/nano-fibers are beneficial to design and manufacture“high strength”CFRP composites.展开更多
Basalt Fiber Reinforced Polymer(BFRP)composites have huge potential application respects for some civil fields due to enough strength/modulus to weight and low cost by replacing carbon fiber composites.Aiming at the i...Basalt Fiber Reinforced Polymer(BFRP)composites have huge potential application respects for some civil fields due to enough strength/modulus to weight and low cost by replacing carbon fiber composites.Aiming at the issues in the Resin-Rich Region(RRR)and Interfacial Transition Region(ITR)of fiber reinforced polymer composites,the characteristic Aramid Pulp(AP)fibers with micro-fiber trunk and nano-fiber branches were manufactured into multiple non-woven ultra-thin interleaving at the interlayers of BFRP composites via compression molding to reinforce the flexural strengths and elastic moduli.AP fibers were introduced into RRR to form interleaving at the interlayer,the brittle epoxy adhesive layer was improved and enabled to avoid cracking under a low external load.Free fiber branches of AP were also embedded into BF layer to construct quasi-vertical fiber bridging behaviors in ITR,stronger mechanical interlocking was created to prevent crack propagation along the bonding interface of BF/epoxy.Three-point bending testing results showed the interleaving film with 4 g/m^(2)AP exhibited the best effect among various areal densities and yielded average 315.75 MPa in flexural strength and 21.38 GPa in elastic modulus,having a 63.4%increment and a 47.1%increment respectively compared with the bases.Overall,the simple and low-cost AP interleaving is confirmed as an effective method in improving interlayer structure and flexural performance of BFRP composites,which may be considered to manufacture high-performance laminated fiber reinforced polymer composites in civil aviation industry.展开更多
Experimental results of 29 axially loaded fiber-reinforced polymer sheet (FS) confined concrete columns and two reference plain concrete columns are introduced. Twenty four column specimens were confined with carbon f...Experimental results of 29 axially loaded fiber-reinforced polymer sheet (FS) confined concrete columns and two reference plain concrete columns are introduced. Twenty four column specimens were confined with carbon fiber sheet (CFS) and five column specimens were hybrid confined with both CFS and glass fiber sheet (GFS). The influence of aspect ratio, FS material, initial axial force ratio, and FS confine-ment degree on the strength and deformation of columns were studied. Based on the experimental results, the equations of complete stress-strain curve of CFS confined concrete are proposed. These equations are suitable for the nonlinear analysis of square and rectangular section columns. Suggestions of applying FS to confine concrete columns are presented.展开更多
基金The National Natural Science Foundation of China(No.51108238)
文摘In order to study the fatigue failure mode and fatigue life laws of basalt-aramid and basalt-carbon hybrid fiber reinforced polymer （ FRP ） sheets, fatigue experiments are carried out, considering two hybrid ratios of 1 ： 1 and 2：1 under different stress levels from 0.6 to 0.95. The results show that fractures occur first in carbon fibers or aramid fibers for the specimens with hybrid ratio of 1： 1, namely B1A1 and B1C1, while a fracture occurs first in basalt fibers for the specimens with a hybrid ratio of 2： 1, namely B2A1 and B2C1. The fatigue lives of the hybrid FRP sheets increase with the improvement of the content of carbon fibers or aramid fibers, and the influence of the carbon fibers content improvement to fatigue life is more significant. The fatigue performance of B2A1 is relatively worse, while the fatigue performance of B1C1 and B2C1 is relatively better. Finally, a new fatigue stiffness degradation model with dual variables and double inflection points is presented, which is applicable to both hybrid and normal FRP sheets.
基金Supported financially by the National Natural Science Foundation of China(No.52102115)the High-end Foreign Expert Recruitment Plan of China(No.G2023036002L)+2 种基金the Natural Science Foundation of Sichuan Province,China(No.2023NSFSC0961)Shock and Vibration of Engineering Materials and Structures Key Lab of Sichuan Province,China(No.23kfgk06)the Postgraduate Innovation Fund Project by Southwest University of Science and Technology,China(No.24ycx2027).
文摘The high-strength Basalt Carbon Fiber Reinforced Polymer(BCFRP)composites had been manufactured by guiding Imitating Tree-root Micro/Nano Aramid Short Fiber(ITMNASF)into the interlayer of Basalt Fiber(BF)and Carbon Fiber(CF)plies to form thin interleaving,and various mass proportions of IT-MNASF were designed to discuss the reinforcing effect on the BCFRP heterogeneous composites.The results of three points bending tests showed that flexural strength and energy absorption of 4wt%IT-MNASF reinforced BCFRP heterogeneous composites had been improved by 32.4%and 134.4%respectively compared with that of unreinforced specimens.The 4wt%IT-MNASF reinforced BCFRP specimens showed both a greater strength and a lower cost(reduced by 31%around)than that of plain CFRP composites.X-ray micro-computed tomography scanning results exhibited that the delamination-dominated failure of plain BCFRP composites was changed into multi-layer BF and CF fabrics damage.The reinforcing mechanism revealed that the introduced IT-MNASF could construct quasi-vertical fiber bridging,and it was used as"mechanical claws"to grasp adjacent fiber layers for creating a stronger mechanical interlocking,and this effectively improved resin-rich region and interfacial transition region at the interlayers.The simple and effective IT-MNASF interleaving technique was very successful in low-cost and high-strength development of BCFRP heterogeneous composites.
基金the National Natural Science Foundation of China(No.52102115)the Fundamental Research Funds of Southwestern University of Science and Technology,China(No.20zx7141).
文摘Compressive strengths and elastic moduli of Carbon Fiber Reinforced Polymer(CFRP)composites can be noticeably improved by multiple ultra-thin interlays with non-woven Aramid Pulp(AP)micro/nano-fibers.10-ply CFRP specimens with 0,2,4,6,8 g/m^(2)AP were tested under uniaxial compression.Those flexible AP fibers,filling the resin-rich regions and further constructing the fiber bridging at the ply interfaces,can effectively suppress delamination growth and lead to very good improvements both in the compressive strength and the elastic modulus.The CFRP specimen with an optimum interlay thickness has a distinct shear failure mode instead of the typical delamination cracking along the direction of continuous carbon fibers.Compressive Strengths After Impacts(CAI)of 12.35 J were also measured,up to 90%improvement in CAI has been observed.It is concluded those ultra-thin interlays of non-woven AP micro/nano-fibers are beneficial to design and manufacture“high strength”CFRP composites.
基金supported financially by the National Natural Science Foundations of China(No.52102115)the Overseas High-End Talent Introduction Project of Sichuan Province,China(No.2023JDGD0013)the Natural Science Foundations of Sichuan Province,China(No.2023NSFSC0961)。
文摘Basalt Fiber Reinforced Polymer(BFRP)composites have huge potential application respects for some civil fields due to enough strength/modulus to weight and low cost by replacing carbon fiber composites.Aiming at the issues in the Resin-Rich Region(RRR)and Interfacial Transition Region(ITR)of fiber reinforced polymer composites,the characteristic Aramid Pulp(AP)fibers with micro-fiber trunk and nano-fiber branches were manufactured into multiple non-woven ultra-thin interleaving at the interlayers of BFRP composites via compression molding to reinforce the flexural strengths and elastic moduli.AP fibers were introduced into RRR to form interleaving at the interlayer,the brittle epoxy adhesive layer was improved and enabled to avoid cracking under a low external load.Free fiber branches of AP were also embedded into BF layer to construct quasi-vertical fiber bridging behaviors in ITR,stronger mechanical interlocking was created to prevent crack propagation along the bonding interface of BF/epoxy.Three-point bending testing results showed the interleaving film with 4 g/m^(2)AP exhibited the best effect among various areal densities and yielded average 315.75 MPa in flexural strength and 21.38 GPa in elastic modulus,having a 63.4%increment and a 47.1%increment respectively compared with the bases.Overall,the simple and low-cost AP interleaving is confirmed as an effective method in improving interlayer structure and flexural performance of BFRP composites,which may be considered to manufacture high-performance laminated fiber reinforced polymer composites in civil aviation industry.
基金Supported by the National Natural Science Foundation of China (No. 50238030)
文摘Experimental results of 29 axially loaded fiber-reinforced polymer sheet (FS) confined concrete columns and two reference plain concrete columns are introduced. Twenty four column specimens were confined with carbon fiber sheet (CFS) and five column specimens were hybrid confined with both CFS and glass fiber sheet (GFS). The influence of aspect ratio, FS material, initial axial force ratio, and FS confine-ment degree on the strength and deformation of columns were studied. Based on the experimental results, the equations of complete stress-strain curve of CFS confined concrete are proposed. These equations are suitable for the nonlinear analysis of square and rectangular section columns. Suggestions of applying FS to confine concrete columns are presented.
